Abdominal laparoscopic surgery gained popularity in the late 1980s, when benefits of laparoscopic removal of the gallbladder over traditional (open) operation became evident. Reduced postoperative recovery time, markedly decreased post-operative pain and wound infection, and improved cosmetic outcome are well established benefits of laparoscopic surgery, derived mainly from the ability of laparoscopic surgeons to perform an operation utilizing smaller incisions of the body cavity wall.
Laparoscopic procedures generally involve insufflation of the abdominal cavity with CO2 gas to a pressure of around 15 mm Hg. The abdominal wall is pierced and a 5-10 mm in diameter straight tubular cannula or trocar sleeve is then inserted into the abdominal cavity. A laparoscopic telescope connected to an operating room monitor is used to visualize the operative field, and is placed through a the trocar sleeve. Laparoscopic instruments (graspers, dissectors, scissors, retractors, etc.) are placed through two or more additional trocar sleeves for the manipulations by the surgeon and surgical assistant(s).
Recently, so-called “mini-laparoscopy” has been introduced utilizing 2-3 mm diameter straight trocar sleeves and laparoscopic instruments. When successful, mini-laparoscopy allows further reduction of abdominal wall trauma and improved cosmesis. Instruments used for mini-laparoscopic procedures are, however, generally more expensive and fragile. Because of their performance limitations, due to their smaller diameter (weak suction-irrigation system, poor durability, decreased video quality), mini-laparoscopic instruments can generally be used only on selected patients with favorable anatomy (thin cavity wall, few adhesions, minimal inflammation, etc.). These patients represent a small percentage of patients requiring laparoscopic procedures. In addition, smaller 2-3 mm incisions may still cause undesirable cosmetic outcomes and wound complications (bleeding, infection, pain, keloid formation, etc.).
Since the benefits of smaller and fewer body cavity incisions are proven, it would be desirable to perform an operation utilizing only a single incision. An umbilicus is well-hidden and the thinnest and least vascularized area of the abdominal wall. The umbilicus is generally a preferred choice of abdominal cavity entry in laparoscopic procedures. An umbilical incision can be easily enlarged (in order to eviscerate a larger specimen) without significantly compromising cosmesis and without increasing the chances of wound complications. One drawback with entry through the umbilicus, however, is that the placement of two or more standard (straight) cannulas and laparoscopic instruments in the umbilicus, next to each other, creates a so-called “chopstick” effect, which describes interference between the surgeon's hands, between the surgeon's hands and the instruments, and between the instruments. This interference greatly reduces the surgeon's ability to perform a described procedure.
Thus, there is a need for instruments and trocar systems which allow laparoscopic procedures to be performed entirely through the umbilicus or a surgical port located elsewhere while at the same time reducing or eliminating the “chopstick effect.”